In September of 2020, JAMA Network Open reported on a pooled cohort study – Association Between Sleep Duration and Cognitive Decline – which demonstrated an, “inverted U-shaped association between sleep duration and global cognitive decline (that) was found, indicating that cognitive function should be monitored in individuals with insufficient (less than or equal to 4 hours per night) or excessive (greater than or equal to 10 hours per night) sleep duration.”
It’s estimated that 12% of the global population is 60 years of age or older – with an estimated increase to one-fifth of the population by 2050.
Dementia, a common feature of old age, affect 50 million people world-wide, according to the World Health Organization – with roughly 14 percent of Americans 71 years and older at risk. Sixteen percent of women older than 71 suffer from dementia compared to 11 percent of men.
Mayoclinic.org notes that, “dementia describes a group of symptoms affecting memory, thinking, and social abilities severely enough to interfere with your daily life. It isn't a specific disease, but several different diseases may cause dementia.”
The website further states that, “though dementia generally involves memory loss, memory loss has different causes. Having memory loss alone doesn't mean you have dementia. Alzheimer's disease is the most common cause of a progressive dementia in older adults, but there are a number of causes of dementia. Depending on the cause, some dementia symptoms may be reversible.”
The JAMA pooled study data - which included results from the English Longitudinal Study of Ageing (2008-2017) and the China Health and Retirement Longitudinal Study (2011-2015) - used a randomly enrolled group of 28,756 people over 50 years of age living in England and individuals over 45, residing in China.
The sleep data was determined from self-reported sleep duration – based on face-to-face interviews, while cognitive function assessed three aspects of memory, executive function, and orientation.
The Chinese study investigators, “found that extreme sleep duration at baseline, including 4 hours or less or 10 hours or more per night, was statistically, significantly associated with faster cognitive decline during 100,000 person-years of follow-up.”
The Chinese researchers recommend that, “future mechanism studies and intervention studies examining the association between sleep duration and cognitive decline are needed.”
You might talk to your physician about the benefits of the essential omega-3 fatty DHA to improve cognitive function – along with either ginkgo biloba or phosphatidyl serine – to see if they fit your health profile.